| Several forms for wireless power transfer exists - Microwave, Laser, Sound, Inductive, Capacitive etc. Among these, the Inductive Power Transfer Systems (IPT) are the most extensively used form of wireless power transfer. Due to the utilization of magnetics the inductive power transfer system suffers from Electromagnetic Interference (EMI) issues. Due to the utilization of magnetic field to transfer power, the system is not preferred in an environment with metals and cannot transfer power through metal barriers.;Capacitive Power Transfer System (CPT) is an emerging field in the area of wireless power transfer. The antennae of the CPT system, constitute two metal plates which are separated by a dielectric (air). When energised, the metal plates along with the dielectric resemble a loosely coupled capacitor, hence the term capacitive power transfer. The capacitive system utilizes electric field to transfer power and therefore eliminating electromagnetic interference issues. The system has low standing power losses, good anti-interference ability. The advantages, make the CPT system a dynamic alternative to the traditional wireless inductive system.;As the area is still in its infancy, the first part of this thesis is dedicated to an extensive study on the literature available on the CPT systems and the basic operation of the system. From, the study it was evident that CPT systems have efficiencies ranging between 60% to 80%. The major limitation apart from its poor efficiency was that the systems were predominately utilized for low power and small air-gap (less than 1cm) applications. This was mainly due to the development of very high voltages across the plates of the capacitive interface.;The main aim of the thesis, is to develop a high power system for small and large air-gaps applications, concurrently possessing high efficiency. To tackle the problems stated, two modified converters where proposed. The first proposed topology could yield higher power transfer for small air-gap applications. The topology proposed exhibits better efficiency and has several advantages compared to the existing topologies for small air gap applications. The second topology is called the Dual LC topology, which reduces the voltage stress across the capacitive interface enabling the CPT system to be used for large air gap applications. The Dual LC topology showcases excellent efficiency for variation in air-gap and under misalignment conditions. In final section of this thesis, the CPT system is extended to charging an industrial electric vehicle (IEV). As the requirement of charging an IEV varies depending on its battery pack. The power flow and control for the CPT systems is implemented. |
